1. Technical Field
The present disclosure relates to a method of controlling creep torque in a motor driven vehicle which is devised to prevent the vehicle from consuming an excessive amount of energy and unintentionally accelerating on a downhill incline.
2. Description of the Related Art
Vehicles driven by an electric motor, such as electric vehicles, hybrid vehicles and fuel cell vehicles, require additional control for creep travel since they have no idle torque, unlike internal combustion engine vehicles. In addition, since step control may cause ride discomfort when performed during the application of creep torque, a smooth torque is output to the motor through filtering. In the calculation of a time constant for the filtering, determination of the time constant of the torque filter in the creep torque control has the following trade-off relationship:
1. The time constant is reduced for the purpose of smooth creep departure of the vehicle (in particular, in the case of driving uphill).
2. The time constant is increased in order to reduce abruptness during departure and reduce the creeping connection of a brake during braking (in particular, on a flat surface or a downhill incline).
Therefore, the smaller the time constant is, the more excessive the creep torque is. This excessively increases the amount of acceleration during downhill departure.
The information disclosed in the Background section is only for the enhancement of understanding of the background of the disclosure, and should not be taken as an acknowledgment or as any form of suggestion that this information forms the related art that would already be known to a person skilled in the art.